The cornerstone or principal stone of a building.
A gravestone, a grave marker: a monument traditionally made of stone placed at the head of a grave.
The keystone of an arch.
Any of the corner building blocks of a building, usually larger or more ornate than the surrounding blocks.
A number of apple varieties with a distinctive ribbed appearance, like corners of a coin.
A metal wedge which fits into the space between the type and the edge of a chase, and is tightened to fix the metal type in place.
A wedge of wood or iron put under the breech of heavy guns or the muzzle of siege-mortars to raise them to the proper level.
To wedge or steady with quoins.